Explosionproof telephone



Aprifl211,1936. R ES ER" mszsm EXPLOSIONPROOF TELEPHONE Filed June 28,1955 2 Sheets-Sheet 1 TOR.

ATTORNEYS.

M 1936- R. F. LESTER EXPLOS IONPROOF TELEPHONE Filed June 28, 1955 2Sheets-Sheet 2 ATTORNEYE.

Patented Apr. 21, 1936 UNITED STATES PATENT OFFICE EXPLO SIONPROOFTELEPHONE tion of New York Application June 28, 1935, Serial No. 28,900

9 Claims.

This invention has for its object, an entirely closed, explosion proofbox for housing a dial telephone mechanism, and particularly aconstruction whereby the dial mechanism is operable from an extensiondial on the outside of the box, and the receiver, or the combinedreceiver and microphone or transmitter, carried by an extension cradle,or rest, on the outside of the closed box.

It further has for its object, an arrangement of the motion transmittingmeans between the extension dial and the extension receiver, and thedial and switch of the telephone mechanism respectively, whereby outletpassages with large surface areas are provided to retard and cool theoutlet of heated exploded gases from the interior of the box so that thegases are cooled below. the ignition point of volatile vapors that maybe in the surrounding atmosphere.

Other objects will appear throughout the specification.

In general, the box is intended for use in situations where there arevolatile explosive gases in the surrounding atmosphere, such as inmines,

oil fields, distillation plants, gas houses, gasoline stations, etc. Itwill be understood that insuch situations, ignitable gases and vaporswithin the box are liable to be ignited by sparks occurring during theoperation of switches and the like 3 within the telephone mechanism,operable during the dialing, or during the opening of the switch, andoperable by the removal of the receiver from its rest. Explosions causedby sparking are, by this invention, confined within the 35 box, and theescaping gases cooled before they find their way to the surroundingatmosphere.

The invention consists in the novel features and in the combinations andconstructions hereinafter set forth and claimed.

40 In describing this invention, reference is had to the accompanyingdrawings in which like characters designate corresponding parts in allthe views.

Figure 1 is a front elevation of this box and 5 contiguous parts of thetelephone apparatus.

Figure 2 is a vertical, sectional view on Figure 1. a

This box comprises a body I, and cover 2, the body being of impervious,non-combustible ma- 50 terial and strong enough to withstand explosions.

They are usually castings.

3 designates, generally, the telephone mechanism; 4 the dial thereof,and 5 the bell switch which is normally closed and held closed by the 55receiver, or the combined receiver and microphone, or transmitter, andopened by the lifting of the receiver from its rest, or cradle.

The dial is of the usual rotary type, rotatable from a starting or zeroposition through various radial angles depending on which of the holes 5of the dial the finger is inserted into for turning the dial untillimited by a finger stop.

The movable door 2 closes an opening in one Wall of the body of the box,through which the telephone mechanism is removable and rep'lace- 10 able'when the door is removed or opened. This door is here shown ascircular, and as screw threaded into an annular flange 8 on the frontface of the box.

9 is an extension dial which is practically a duplicate of the dial 3and operable through the same angles as the dial 4, it being limited inits movement by a stop I0 fixed to the door 2. Suitable motiontransmitting means is provided between the extension dial 9 and the dial4, the 20 extension dial being here shown, and preferably, carried bythe door and including a coupling which uncouples from the dial 4 whenthe door is removed, or opened, and couples therewith when the door isreplaced, or closed. The motion 25 transmitting means is here shown as ashaft II journalled in the door 2 coaxially therewith, and alsocoaxially with the dial 3, the extension dial 9 being mounted on theouter end of the shaft I I, and the coupling including a crank arm I2 onthe inner end of the shaft I I and having a crank pin which fits intoone of the holes of the telephone dial 3, usually the zero hole, or thehole nearest the stop corresponding to the stop I0. The shaft II is hereshown as journalled in a bushing I3 mounted in the door 2, and the dooris cup-shaped, and the bushing mounted in an elongated hub or bearinglocated on the inner side of the door and terminating near the dial 4 inorder to provide a long bearing for the rock shaft II. The purpose ofthe long bearing and shaft is to provide surfaces of large area withwhich any heated gases must come in contact in finding their way outalong the shaft II, these large surfaces baffling, or retarding, andcooling the gases during their passage outward, to a point below theignition point of any volatile vapors in the surrounding atmosphere.

Likewise, the threaded contact between the door 2 and the flange 8provides retarding and cooling surfaces of sufiicient area to cool theheated gases below their ignition point before they find their way tothe outer atmosphere. The. dial 9 is mounted on a reduced, flattened endI4 of the shaft I I and abuts against a shoulder at l5 thereon. It isheld in position by a cap nut I6. The dial 9 is thus keyed to the shaftII to transmit a rotary movement thereto. The reduced end is oblong andextends diametrically of the outer end of the shaft H, the end of theoblong being threaded to receive the threads of the nut. The dial 9 hasa complemental oblong slot to receive the reduced end.

Means are provided for locating the door 2 when it is screwed into thebody to such position that the finger stop 10 is located injuxtaposition to the zero position of the dial 4 of the telephonemechanism, this means being here shown as a set screw l1 threadingthrough a flange on the periphery of the cover and coacting with a spot,or depression, H8 in the edge of the flange 8.

In operation, the door 2 is screwed into the flange 8, and the shaft 1 Ibeing rotatably mounted therein does not turn, but is allowed to hangvertically downwardly and therefore, passes into the zero hole of theinner dial 4. Then, in order to locate the finger stop II], which iscarried by the door, the door is turned, when in nearly its finalposition, until the set screw I! is in line with the spot l8, and theset screw I I tightened.

The extension means for operating the switch 5, as here shown, includesan axially movable rod slidable in an extension bushing 26 threadinginto the top wall of the box, the rod having a foot 21 at its lower endcoacting with the operating member 28 of the switch 5 and carrying, atits upper end above the bushing, a head 29 for coacting with thecombined receiver and microphone or transmitter 30 when on its rest. Theweight of the receiver and microphone unit causes the rod 25 to movedownwardly and close the switch 5. The movement downwardly is againstthe action of a suitable returning spring 3| located in a counterbore 32in the upper end of the bushing 26, the spring encircling the rod andabutting at one end against the bottom of the recess, and at its otherend against the head 29 at the upper end of the rod 25. The head 29 issecured to the red by a screw 33. The intermediate part, or yoke, of thereceiver or microphone unit presses on the head 29 and holds the roddepressed and the switch 5 closed. The bushing carries a cradle 34 forthe receiver and microphone unit, the bushing and the cradleconstituting an extension rest for the unit. The sliding surface contactbetween the rod 25 and the bushing is of sufllcien-t extent to providesurfaces of large enough area to retard and cool the gases during thepassage of the heated gases out along the rod 25. The rod 25 is heldfrom undue upward movement by the spring, when the receiver is removed,by a stop washer 36 located in a groove 31 in the lower end portion ofthe rod 25 in position to abut against the lower end of the bushing 25when the receiver is removed. I

The body of the box is also provided with bosses 40 which may bethreaded to receive a conduit line enclosing the surface wires, and isalso provided with a connector 4| to receive the cord 42 which connectsthe telephone apparatus within the box with the receiver andtransmitter. The box is also formed with suitable means as lugs 38 bywhich it can be secured to a wall, post, or other support.

What I claim is:

1. A box for completely enclosing a dial telephone mechanism whichincludes a manually operable dial and a switch having a movable memberoperable by the removal of the receiver from its. rest, said boxcomprising a body and a movable door through which the telephonemechanism is removable and replaceable, an extension dial carried by thedoor on the outer side thereof, motion transmitting means between thelatter dial and the dial of the telephone mechanism within the box, areceiver rest on the outside of the box, and motion transmitting meansbetween the receiver on said rest and the movable member of the switch,whereby the switch is operated by the removal of the receiver from, andreplacement on its rest.

2. A box for completely housing a dial telephone mechanism whichincludes a manually operable dial and a switch having a movable memberoperable by the removal of the transmitter, said box comprising a bodyand a movable door through which the telephone mechanism is removableand replaceable, an extension dial carried by the door on the outer sidethereof, motion transmitting means between the latter dial and the dialof the telephone mechanism Within the box, a receiver rest on theoutside of the box, and motiontransmitting means between the receiver onthe rest and the movable member of the switch, whereby the switch isoperated by the removal of the receiver from, and replacement on itsrest, the door and the box having passages for said motion transmittingmeans in which said means slidably fit.

3. A box for completely housing a dial telephone mechanismwhich includesa manually operable dial and a switch having a movable member operableby the removal of the receiver from its rest, said box comprising a bodyand a movable door through which the telephone mechanism is removableand replaceable, an extension dial carried by the door on the outer sidethereof, motion transmitting means between the latter dial and the dialof the telephone mechanism within the box, a receiver rest on theoutside of the box, and motion transmitting means between the receiveron the rest and the movable member of the switch, whereby the switch isoperated by the removal from, and replacement of the receiver on itsrest, the door and the box body having passages for said motiontransmitting means, the motion transmitting means and the walls of thepasages being formed to provide surfaces of sufiicient area to retardand cool the outlet of heated exploded gases from the box.

4. A box for completely enclosing a dial telephone mechanism whichincludes a manually operable dial, and a switch having a movable mem beroperable by the removal of the telephone receiver from itsrest, a dialcarried on the outer side of the box, motion transmitting means betweenthe latter dial and the dial of the telephone mechanism, an extensionreceiver rest on the outside of the box, and motion transmitting meansbetween the receiver on the rest and the movable member of the switch.

5. A box for completely enclosing a dial telephone mechanism whichincludes a manually'operable dial and a switch having a movable memberoperable by the removal and replacement of the telephone receiver fromand on its rest, a dial carried on the outer side of the box, motiontransmitting means between the latter dial and the dial of the telephonemechanism, and an extension receiver rest on the outside of the box, andmotion transmitting means between the rest and the movable member of theswitch, the box being provided with elongated passages in which saidmotion transmitting means slidably fit providingsurfaces of sufiicientlylarge area to retard and cool the outlet of heated exploded gases fromthe box.

6. A box for completely enclosing a dial telephone mechanism whichincludes a manually operable dial, and a switch having a movable memberoperable by the removal and replacement of the telephone received fromand on its rest, said box having a door through which the telephonemechanism is removable and replaceable, the door being coaxial with thedial and removable and replaceable by a rotary and axial movement, arock shaft journalled in the door coaxially therewith and coaxially withthe dial, an extension dial mounted on the shaft on the outside of thedoor, a coupling at the inner end of the shaft and coacting with thedial of the telephone mechanism to transfer the rotary movement of theshaft to the dial of the telephone mechanism, an extension receiver reston the outside of the box, and means housed in the rest for operatingthe switch of the telephone mechanism when the receiver is removed fromand replaced on the extension rest.

7. A box for housing a dial telephone mechanism which includes amanually operable dial, and a telephone switch having a movable memberoperable by the removal and replacement of the telephone receiver fromand on its rest, said box having a movable door through which thetelephone mechanism is removable and replaceable, a rock shaftjournalled in the door coaxially with the dial, an extension dialmounted on the shaft on the outside of the door, a coupling at the innerend of the shaft and coacting with the dial of the telephone mechanismto transfer the rotary movement of the shaft to the dial of thetelephone mechanism, said coupling coacting with the dial of thetelephone mechanism to uncouple therefrom and couple therewith uponopening and closing movements of the door, an extension receiver rest onthe outside of the box, and means housed in the rest for operating theswitch of the telephone mechanism when the receiver is removed from andreplaced on the extension rest.

8. A box for housing a dial telephone mechanism which includes amanually operable dial, and a telephone switch having a movable memberoperable by the removal and replacement of the telephone receiver fromits rest, said box having a movable door through which the telephonemechanism is removable and replaceable, a rock shaft journalled in thedoor coaxially with the dial, an extension dial mounted on the shaft onthe outside of the door, a coupling at the inner end of the shaft andcoacting with the dial of the telephone mechanism to transfer the rotarymovement of the shaft to the dial of the telephone mechanism, saidcoupling coacting with the dial of the telephone mechanism to uncoupletherefrom and couple therewith upon opening and closing of the door, thedoor having a hub on its inner side terminating near the dial of thetelephone mechanism in which the rock shaft is journalled providing along passage for the outlet of exploded gases, an extension receiverrest on the outside of the box, and means housed in the rest foroperating the switch of the telephone mechanism when the receiver isremoved from and replaced on the extension rest.

9. A box for housing a dial telephone mechanism which includes amanually operable dial, and a telephone switch having a movable memberoperable by the removal and replacement of the telephone receiver fromand to its rest, said box having a movable door through which thetelephone mechanism is removable and replaceable, the door threadinginto the box and arranged coaxial with the dial of the telephonemechanism, a shaft journalled in the cover coaxial therewith and havinga coupling at its inner end coacting with the dial of the telephonemechanism, and an extension dial mounted on the outer end of the shaft,a finger stop carried by the door for limiting the movement of theextension dial at a pre-. determined point, and means for locating thedoor in its final position with said stop in a predetermined position,an extension receiver rest on the outside of the box including a bushingextending into the box, a rod slidably fitting the bushing and coactingat its inner end with the movable switch member and having its outer endarranged to be engaged and moved inward by the receiver when on therest.

' RAY F. LESTER.

